The determination of HIV antibodies is an important diagnostic task.
Peptide sequences taught in WO 88/08005 and Science 237 (1987), 1346-1349, can be used to detect antibodies to HIV-2, using immunoassays. In the methods of determination described therein, synthetic peptides have to be used in high concentrations and only small signals are obtained with high blank values.
The abstract "DEVELOPMENT OF HIV-1 AND HIV-2 SPECIFIC AND SELECTIVE ENZYME LINKED IMMUNOSORBENT ASSAY BASED 0N TRIPALMITOYL-S-GLYCERYL-CYSTEINYL-PEPTIDES" from the 20th EUROPEAN PEPTIDE SYMPOSIUM, Sept. 4-9, 1988 in Tubingen/FRG teaches that the sensitivity of an HIV-2 assay can be improved by cyclization of a HIV-2 peptide, via two cysteine residues contained therein. However, the Pam.sub.3 Cys-peptide conjugate described therein is not completely suitable for a sensitive HIV-2 test. Large amounts of the conjugate are necessary in order to immobilize the antibodies, and high blank values still result, even though the sensitivity is improved.
Cyclic HIV-2 and HIV-1 peptides are also known from EP-A 0 326 490. These peptides also have to be used in large amounts for immunological tests and the results also show very high blank values.
The object of the present invention is therefore to provide a method for the determination of HIV antibodies with which these disadvantages can be eliminated.